Conventional cutting tools with cartridges, which are adapted to mount cutting inserts, employ various means for securing the cartridges to the cutter body. In some cutting tools, threaded bores are provided in the cutter body and corresponding through bores are provided in the cartridges. The cartridges are secured directly to the cutter body by using screws. Such a method, however, requires various metal cutting operations for producing the threaded bores, which may weaken the cutter body. Further, when the cutting tool is damaged, the part of the screw that breaks off may fall into the threaded bore of the cutter body.
Other conventional cutting tools adopt a structure of securing the cartridge by means of a wedge. Korean Patent Application Laid-Open No. 2005-49530 discloses a cutting tool including cartridges with wedges and serrations. FIG. 1 illustrates a cutting tool according to such prior art. A cutter body 1 is plate-shaped and comprises a plurality of recesses 2. The recesses 2 are arranged at the same interval around its outer circumference. Each of the recesses 2 receives a cartridge 4 for mounting a cutting insert 3. When a screw 6 is fastened into a threaded hole 5 in the cutter body, the outer portion of the screw 6 is received in the recess 2. The position of the cartridge 4 may be finely adjusted in the axial direction of the cutter body as the screw rotates. Once the position of the cartridge 4 is determined, the cartridge is clamped through tightening a wedge 8 by a screw 7.
In the prior art as discussed above, the radial position of the cartridge is determined by serrations 9 on the bottom surface of the cartridge. Further, there is a gap between the inner side surface of the cartridge in the radial direction and the inner side surface of the cutter body, which receives the cartridge. Without such a gap, there may be interference between the two parts, i.e., the cartridge and the body of the cutting tool. Accordingly, the cartridge is supported only by top and bottom surfaces, and there is no support in the radial direction. That is, such a structure of the prior art may not provide a sufficient clamping force for the cartridge.
Further, as the serrations 9 become the reference position for mounting, the manufacture of the cartridges 4 becomes difficult. Also, the radial position of the cartridges after adjustment becomes inconsistent due to manufacturing and assembling errors of the serrations 9. As a result, the accuracy in the cutting processes is significantly deteriorated.